1. Field of the Invention
The invention relates to compositions for improving the appearance of skin, particularly to provide good coverage over imperfections such as pores and uneven skin tone, while retaining a natural skin appearance.
2. The Related Art
A matte effect is often sought from facially applied cosmetics. The matte finish overcomes the shiny effect engendered by greasy skin, particularly under hot and humid conditions. Absorbent fillers such as talc, silica, kaolin and other inorganic particulates have been used to achieve the effect by their optical properties.
Imperfect skin can be hidden in two ways through manipulation of light transmission. In the first, components of the cosmetic may simply reflect light back toward the source. An alternative approach is referred to as achieving a soft focus effect. Here the incoming light is distorted by scattering (lensing). Components of the color cosmetic in this mechanism operate as lenses to bend and twist light into a variety of directions.
While it is desirable to hide imperfect skin through a matte effect, there is also a desire to achieve a healthy skin radiance. A cosmetic covering that is too opaque hides the skin under a paint-like coating. Imperfections are hidden but there is no radiance. Some refer to this as whitening. Where light transmission is insufficiently hindered, the opposite occurs. Here the glow may be healthy but aesthetically displeasing skin topography and color may now be apparent.
U.S. Pat. No. 5,997,890 (Sine et al.), U.S. Pat. No. 5,972,359 (Sine et al.), and U.S. Pat. No. 6,174,533 B1 (SaNogueira, Jr.) are all directed to topical compositions to provide good coverage of skin imperfections. The solution proposed by these documents is the use of a metal oxide with a refractive index of at least about 2 and a neat primary particle size of from about 100 to about 300 nm. Preferred particulates are titanium dioxide, zirconium oxide and zinc oxide.
A significant disadvantage of titanium dioxide and zinc oxide is the whitening effect upon the skin. An undesirable ashen appearance is unfortunately created.
U.S. Patent Application 2005/0287092 A1 (Liechty et al.) reports make-up and skincare compositions in powder form which allow the natural grain of the skin to show through. These powders are based upon barium sulfate particles coated with an N-acylamino acid such as lauroyllysine. Also present is at least one elastomeric organopolysiloxane powder or a polymethylmethacrylate powder.
U.S. Patent Application 2005/0079190 A1 (Polonka) discloses the use of solid single-crystal flat platy particles which in cosmetic skin care compositions provide consumer-desired properties of the appearance of natural skin radiance. Suitable platy particles include bismuth oxychloride, aluminum oxide, zirconium oxide and boron nitride.
U.S. Pat. No. 6,495,123 (Faryniarz et al.) and U.S. Pat. No. 6,432,389 B1 (Hansenne et al.) describe cosmetic compositions with improved skinfeel properties delivered through polymeric porous particles such as methyl methacrylate crosspolymers.
A challenge which has not been fully met by the known art is delivery of a composition with appropriate optics to achieve both soft focus and radiance properties in a system that still provides excellent skinfeel. Still further there is a need which has not previously been fully met for a soft focus system that reduces “red wavelength” to hide fine lines and wrinkles.